Rolling of band iron, hoops, and the like



June 25, 1929. B. WITTING I Y 1,718806- ROLLING OF BAND IRON, HOOPS, ANDTHE LIKE Filed April- 18, 1927 2 Sheets-Sheet 1 lmmmun pIIIIHIWIIIIIIIWIH June 25, 1929. wlTTlNG 7 1,718,806

ROLLING of BAND IRON, Hoors, AND THE LIKE Filed A ril' 18, 1927 2Sheets-Sheet 2 o '0 0 DE 4 Q0 w 0 Q Inventor:

Patented June-25,1929.

PATN OFFIC BRUNO WITTING, OF BON'N-ON-THE-RHINE, GERMANY.

ROLLING F BAND IRON, HOOPS, AND THE LIKE.

Application filed April 18, 1927, Serial No. 184,806, and in GermanyApril 23, 1928.

This invention has reference to rolling means and it refers inparticular to improvements in the rolling of band-iron, hoops and thelike, either of plain or of profilated or '5 figured cross section, andis likewise adaptable to the rolling of metal bands and of similarmaterial of plain and or profilated cross section or other metals butiron, and it is intended toincrease the facility of manipulation and theoutput of the product, and to generally improve the manufacturingprocess. The manufacture of band-iron or hoop-iron and of steel bands ofa thickness of 1 millimeters (0.06 inches) and less has been effectedheretofore generally in such a manner that the billets which have beenpreliminarily rolled in hot-rolling devices to a thickness of 1%millimeters and above were then rolled down to the required thickness incold condition and in special rolling machines. The rolling operationwas effected in several stages in accordance with the thickness requiredbut in such a manner that the reduction of thickness of the cold rolledmaterial at each stage was only a comparatively small one. Thebrittleness and hardness of the material to be rolled has to be overcomeby the repeated burning or annealing of the rolled band of material inspecial annealing ovens, such annealing stages being inserted betweenthe several rolling stages. This manner of procedure which admits ofobtaining only limited outputs, might be greatly improved and renderedmore economical, if it would be possible to roll down the band ofunfinished material produced in the rolling machine to a thickness ofless than only 1% millimeters, in order to thereby decrease the workingprofile of the cold rolling machines. This manner of operation ishowever interfered with by the rapid drop of temperature 0btainod in therolling of iron bands, so that the further reduction of thickness hasheretofore been entirely leftto the treatment of the iron band obtainedin the warm condition by the subsequent action of the cold rollingmachines. In accordance with the previous methods it has been suggestedto heat again the band-shaped material fed to the cold rolling devicesand previously obtained in the hot condition, special devices andfurnaces being provided for the re-heating of the material before itsintroduction to the cold rolling machines, but the results obas tamedare unsatisfactory, because there is either a very rapid overheating ofthe iron band on account of the direct action of the heat concentratedupon a particular point, or the heating of the material was lackin ea inuniformity, so as to obviate the desire purpose.

In accordance with this invention these drawbacks are overcome byproviding fora heating by electrical means and in such a manner that therolling goods to be heated are traversed by the electrical or ,themagnetlc current. Provision may be made to admit the current to therolling goods by induction or bg means of electric contacts, andpreferably t e admission of the current may be effected in several, Iserially arranged length of the rolled goods. In this connectionprovision ma be made to regulate and adjust the strengt of the currentin eachof these several lengths. The regulation .3 be preferablyefiected in such a mannerthat the rolling goods under treatment areheated to the rolling temperature only shortly in front of the rollingdevice. is regulation may be efiected manually or automatieally anddependin upon the temperature of the heated rolle goods. A particu.larly advantageous arrangement will be obtained by causing the currentto pass through the rolled material in the longitudinal directionthereof.

The admission of the current ma for instance be eflected by the tappingo the secondary coil of a transformer at repeated to points, so thatfrom the tapped portions heating currents of difi'erent strengths andpreferably of a strength decreasing in the direction of the rollingoperation may be fed to the different lengths of the rolled material asdisposed between the respective pairs of electrodes.

The admission of the current in this case is efiected by means ofelectrodes distributed along the length of rolled material to be heated,such electrodes being preferably constructed as roller electrodes whichare employed together with the pressure rollers. In order to insure theuniform pressure con tact of these rollers one of the rollers of each wepair of rollers or rolls ma be conducted in inclined guides withrelatlon to the general direction of the passage of the material, so

limited by means of adjustable stops. It is advantageous in thisconnection to impart figured or profilated cross sections to therollers, that is to say to provide them with ribs, flutings or withpoint-ed sections, so as to insure the highest possible uniformity ofthe admission .7 of the current and the greatest intensity thereof.

Instead of arranging the material to be rolled so as'to become part ofone or several secondary circuits of a transformer, the heatin andannealing-of the material to be ro led may also be effected by means ofeddy currents produced by high frequency alternating currents. Thegeneration of the eddy current is preferably eifected in airtransformers without iron cores. As an exemplification a mufile ofrefractory material may be disposed between two roller scaflolds ofusual construction, around which a coil of conducting material and fedwith high frequency alternating current is substantially concentricallyarranged the field of force of which causes the heating to the glowingtemperature of the material to be rolled and introduced intothe interiorof the mufll'e and kept continuously in motion,

so that this material is easily raised to the rolling temperature.

The invention will be more particularly described by reference to theaccompanying drawing showing by way of illustration and exemplificationtwo forms of embodiment of the. principles of this invention. In thedrawings Fig. 1 is a diagram in front View of the arrangement of arolling mill with heating means in front thereof; Fig. 2 is a diagramshowing the electric connections of the circuit used for this purpose;Fig. 3 is another diagram of the general arrangement of the circuit;Fig. illustrates an electrode for the admission of the current to thematerial to be rolled and having the general shape of a profilatedroller; Fig. 5 illustrates a preferred way of mounting the roller elec-'trode; Fig. dis a side View showing diagrammatically a device foreffecting the heating of the goods to be rolled by means of'eddycurrents; Fig; 7 is a diagram illustrating a device for the automaticcontrol of the current strength; Fig. 8 shows diagrammatically anembodiment of means for the automatic regulation of the current and ofthe temperature produced.

In accordance with the arrangement shown in Figures 1 and 2 by way ofillustration a cold rolling machine a ofwellknown construction iscombined with a heating apparatus disposed in front thereof withrelation to the passage of the material. Both devices may be supportedeach on a separate base or they may be combined in any suitable manner,so as to constitute a unitary whole. By means of this heating apparatusthe otherwise well-known procedure is most advantageously carried outaccording to which a piece of work of iron or other metal of a certaincross section and introduced between the two terminals of a dynamomachine is immediately heated upon the switching into circuit of theelectric current.

The mode of operation of the heating apparatus, as appears from thediagram of Fig. 2, is substantially as follows: Through the primarywinding h an electric current of ordinary voltage is caused to flowwhich in the secondary winding 0 induces a current of low voltage but ofhigh intensity which latter current is conducted to the terminals e and7 which for the purposes of the invention constitute roller electrodes.The current traverses the iron band 9 which is forced by the. pressure.rollers d against the electrodes and constitutes the shortest waybetween the terminals 6 and f, and by this the particular degrees oftemperature which may be adjusted by special regulating and controllingmeans.

In order to spread. the heating along a greater extent of the materialto be rolled, so as to prevent unnecessary strains on the material, aplurality of pairs of electrodes serving for the admission and thedischarge of the current are serially arranged and are fed by separatesources of current, such as for instance transformers; the band of iron9' (Figures 1 and 2) on its way from the reel or the like, not shown, tothe rolling machine a passes successively through the pairs ofelectrodes under the action of the pressure rollersd. The iron bandwhich, so to speak, has been pro-heated between the first pair ofelectrodes 6 is-made to pass on to the next and higher heating zone andthus in succession, until the band between the .rolling method accordingto this invention which presents the additional advantage of doing awaywith the necessity of burning the rolled iron band between the severalstages the method according to this invention pic I sents the greatadvantage of maintaining the heating apparatus continuously in properoperating condition, so as to produce sharply defined temperatures inthe several heating zones, while on the other hand the blistering of theiron band and consequently the formation of cinders and slags areexcluded. 'The process may also be applied with great commercial successfor the rolling out of certain predetermined profilated shapes of ironfrom band iron or fiat iron, thus for instance of slotted tubes in whichcase the skelp before the introduction into the calibrated rollers issubmitted to a gradual heating to the rolling temperature required forthe ready moulding of the material.

The pos ibility of maintaining certain sharply defined temperaturesrenders the invention particularly adapted for the finishing rolling ofbands, profiles, channel irons, pipes or the like from other metals butiron in the working of which the success of the treatment would beannihilated by the exceeding of the critical rolling temperatures. Theabsolutely uniform heating of the unfinished metallic piece of work, thefacility and reliability of the regulation of the temperatures inaccordance with the method of the invention obviate the liability of anyinjurious overheating of the metals to be submitted to the furthertreatment.

The method of admitting the current to the materialto be rolled, asexemplified diagrammatically in Fig. 3 of the drawing has been shown tobe particularly advantageous in the practical operation of the process.

In Fi 3 2' indicates the secondary coil of a trans ormer the primarycoil of which is not indicated, in order to avoidcomplication. Thesecondary coil 71 is tapped at is, Z

and at m and. n. The end is of this second-' ary coil 71 is connected tothe contact roller 0 and the other end n of the secondary coil z' isconnected to the contact roller 0 and the band to be heated is moved inthe direction of rollers 0 0 the roller 0 being arranged directly infront of the finishing rolling device. The secondary coil 6 is alsotapped at Z and m and the tapped shunts are cono 0 0 0 bear the ratio6:3:1, so that for instance 9 kw. is fed to the length 0 0 while 4, 5kw. is admitted to the section o 0 and 1, 5 kw. is admitted to thesection o,,0 This object may for instance be accomplished byadmitti'ngGOO amps. current each to the contacts 0 0 and 0 so thatthrough the contact 0 a total contact of 3 times 600=1800 amps. iscaused to flow to the secondary. coil.

while the section 0 0 is traversed by a current of twice 600=1200 amps.and the section 0 0 by a current of 3 times 600=1800 amps; Consideringthe voltages necessary forthe production of the current strengthmentioned this arrangement will result in the distribution of energy tothe several sections hereinbefore indicated. 7

By means of this method of the admission:

In this case the section 0 0 is traversed by a current of 600 amps,

The electrode employed for the admission, of the electric current asindicated diagrammatically in Figures 1 and 3 of [the In order to arriveat a perfect and complete saturation of the drawing may be in the shapeof ordinary smooth rollers or rolls.

surfaces of the material to be heated and to be rolled with the amountsof energy fed thereto, and to obtain the uniform conversion of theseamounts of energy trodes admitting the current, as shown by way ofexample inFigure 4 of the drawing, may have theirouter surface suitablyinto heat in the rolling goods the elecprofilated or provided withblade-like projections p, as shown in Fig. 4 of the drawing, or withpointed parts, in order to produce the crowding of the amounts ofelectricity admitted in the transmission of the current. The profilatedportions may be of straight or undular configuration or may assume anyother suitable shape. In order to relieve the heated section of rollingmaterial as much as possible from mechanical strain an additionalrolling scaffold g'may be disposed infront of the electrodes 0. asindicated in Fig. 5, by meansof which the rolled material is admitted tothe main rolling scafiold a at the required rate, so that neither atensional strain nor a pressure will be produced between the two rollingscaffolds in the rolled material.

In order to obviate the liability of interruptions in the distributionof the current by deficient or changing formations of the points ofcontact, care should be taken to insure permanently good formation ofcontact, and in view of this object the arrangementshowndiagrammatically in Figure (3 of the drawing may be used. Intlusligure:-o and s are the two bearing sockets of a pair of contact-rollersor rolls. The

socket bearing 8 is arranged in the journal body t, so as to bedisplaceablein the direction of the arrow u, and its displacement islimited, by the screw '0. The adjustment of the socket bearing .9 bymeans of the screw 'v a is effected in such a manner that the center 411of the upper bearing socket 8 is somewhat staggered with relation to thecenter w of the lower bearing 1', and in the direction of the passage ofthe metal band as. This direction of the passage of the material isindicated by the arrow 3 If the metal band is moving in the direction ofthe arrow, it will carry the upper roller which will, of course, firstassume such a position that its center axis is disposed vertically abovethe center axis of the lower roller along with it in the direction ofits path. By means of the upper inclination of the bearing socket thistendency will cause the roller beingmore firmly forced against the bandpassing between the rollers. This movement of the upper roller isterminated, as soon as the shaft of this roller or roll becomes engagedwith the semi-circular bearing surface of the socket 8. By theadjustment of the bearing socket s by means of the screw '0 thecontacting pressure may be regulated and stoppage and pinching of theband is prevented.

The screw, instead of operating upon the bearing socket smay of coursebe made to act directly upon the shaft of the roller. It should beunderstood that this manner of adjustment is provided .at both endsofthe roller.

In further pursuance of my invention means are provided to carry out themethod of the invention without the use of sliding or roller contacts,as particularly indicated diagrammatically in Fig. 7 of the drawing. Inthis figure the operating rollers are genorally indicated by the lettersA .and A while B and B are the conveying rollers. By means of thcserollers B and B the material S to be rolled is conducted through theheating mufile M to the pressure rollers A and A The heating muflle Mwhich may consist of refractory clay or similar material is surroundedby the high frequency coil P At the rear of the working rollers A and Aanother muffle M is arranged in which the material which has been formedby the pressure rollers is subjected to an annealing process, in orderto eliminate the brittleness and the other changes of physical qualities-of the rolled material occurrlng during the rolling operation. Themuflie M is likewise surrounded by a concentrically disposed coil P5which may. either be serially connected to the coil P or which, ifdesired, may also be fed from the high frequency line circuit, and ifdesired, by the admission of alternatmg'currents of different voltageintensity or number of periods in accordance with the particular natureof the piece of work to be heated.

In the practice of this invention it has been found to be particularlyadvantageous, -to feed the coils with high frequency alternatingcurrents which in aceordance'with the size of the material .to be rolledmay be worked at a frequency up to ten thousand periods per second andabove. The coils material introduced into the interior of the mufile andwhich is kept continuously moving, to be heated to the glowingtemperature and consequently to the proper temperature for the rollingoperation. In this arrangement the coupling of the primary and secondaryalternating currents by means of a closed iron core is avoided and thetransformer is of the type of an air transformer without iron core.

In the method according to this invention it is of particular importanceto adhere to certain definite temperatures of the material to be rolled,in order to avoid damaging thereof by overheating or to preventirregularities in the process as a result of irregular heating. Bycontrolling the admission of the current and consequently the heating byhand this uniformity of operation cannot be fully accomplished. It istherefore preferable to effect this regulation automatically anddependent upon the temperature of the rolled material. This automaticregulation is particularly of importance in view of the fact thatfractions of seconds are sufficient for the overheating of the heatedmetal which has been heated forinstance to bright red heat, by theadmission of too strong a current. A preferred way of the automaticregulation of the heating operation is shown for instance in Fig. 8 ofthe drawing.

In this figure, l is a selenium cell upon which by means of a lens 2 thelight of the glowing color of the metal 3 to be heated is projected. Thesource of current feeds the two circuits 4 and 4 The circuit 4,,contains the electromagnet 5 and the circuit 4., contains theelectromagnet 5 In the interior of the electromagnets 5 and 5 the ironcores 6 and 6 are respectively arranged which are suspended from theends of a chain 8 passing by way of the sprocket rollers 7 and 7,,.Intermediate these rollers 7.l and 7 the contact race 9 is provided atthe contacts of which tapped branch conduits of a regulating andcontrolling transformer not shown in the drawing are caused toterminate. Along the contact race 9 the contact slide 10 which issecured to the chai 8 is adapted to slide.

The selenium cell 1 is included in the circuit 4 of the electromagnet5,, while in the circuit 4., of the electromagnet 5 a manuallyadjustable resistance 11 is included.

The mode of operation of this part of out of the method the device forthe carrying u f 1 stantla y as 0 of this invention is su lows: 4

By the adjustment of the selenium cell 1 or by the adjustment of theresistance 11 the device will be set in such a manner that at a certaincolor of the hot glowing material, thus for instance at bright red heat,the two electromagnets 5 and 5,, will counterbalance each other. As soonas by more than the nornormal heating of the metal the irradiation ofthe selenium cell 1 becomes more intense the conductivity of said cellis increased, so that a stronger current will flow through the circuit 4and as a result thereof the force of the electromagnet 5 will exceed theforce of the electromagnet 5 In view thereof the chain 8 and inaccordance therewith the contact 10 are displaced and by this means acertain amount of convolutions of the secondary coil of a transformerwhich furnishes the heating current are cut out, if as an instance anumber of tapped conduits of a transformer, say nine of such conduits,are connected to the contacts of the contact race as above set forth,and it becomes pos-.

sible thereby to reduce the heating current. On the other hand, if as'aresult of changing conditions the degree of heating pf the heated metalbecomes reduced, the resistance of the selenium cell 1 irradiated bymeans of the lens 2 is increased, so that the current flowing throughthe coil of the electromagnet 5 is reduced. In this case the force ofthe electromagnet 5 will then exceed the force of the electromagnet 5 sothat by means of the chain 8 the contact 10 is caused to move in theopposite direction, thereby including additional convolutions of thesecondary coil of the transformer fur-- nishing the heating'current. Bymeans of the device described it becomes possible to automatically cutin and out regulating and controlling resistances included in theheating current with similar advantage.

Instead of effecting the regulation by direct means, it may also beeffected by the intermedia of relays.

These arid other modifications and alterations may be effected incarrying out the method according to this invention and in the buildingup of the apparatus for its most advantageous execution, and withoutthereby deviating from thescope and spirit of the invention as efined inthe appended claims.

I claim a 1. The method of effecting the finishing rolling ofsubstantially band-shaped and similar metallic material, which consistsin first rolling the material substantially to the desired crosssectional shape, cooling it, then submitting it to the successive actionof different amounts of electric energy, while keeping the material inmotion, thereby gradually re-heating the material and finally submittingit to finlshing rolling.

2. The method of effecting the finishing rolling of substantiallyband-shaped and similar metallic material, which consists in firstrolling the material to substantially the desired cross sectional shape,cooling it, and then submitting the material to movement in its axialdirection and to gradual electric re-heating in successive stages ofdifierent electrical intensities, while in motion, and finallysubmitting it to finishing rolling.

3. The method of effecting the finishing rolling of substantiallyband-shaped and similar metallic material, which consists'in firstrolling the material to substantially the desired, cross sectionalshape,moving it in the axial direction and submitting it-to the heating actionof different intensities of electric alternating currents while inmotion, anlrll after heating submitting it to finishing r0 mg.

4. The method of effecting the finishing rolling of substantiallyband-shaped and similar metallic material, which consists in firstrolling the material to substantiall the desired cross sectional shape,allowing it to cool, moving it in the axial direction, inserting it inthe secondary circuit of a transformer while in motion, and finallysubmitting it to finishing rolling.

5. The method of effecting the finishing rolling of substantiallyband-shaped and similar metallic material, which consists in firstrolling the material to substantially the desired cross sectional shape,allowing it to cool, moving it in the axial direction and inserting itin the secondary circuit of a step-down alternating current transformerwhile in motion, and finally submitting it to finishing rolling.

6. The vmethod of efl'ecting the finishing rolling of substantiallyband-shaped and similar metallic material, which consists in firstrolling the material to substantially the desired cross sectional shape,movin it in the axial direction, submitting it wl iile in motion to theaction of high frequency electric currents, thereby producing eddy currents in such material and finally submitting it to finishing rolling.

7. The method of effecting the finishing rolling of substantiallyband-shaped and similar metallic material, which consists in firstrolling the material to substantially thedesired cross sectional shape,allowing the material to cool, then gradually re-heating it by electricmeans, regulating the heat of each particular stage automatically inaccordance with the heating color of such stage, and finally submittingthe re-heated material to finishing rolling.

8. The method of effecting the finishing rolling of substantiallyband-shaped and similar metallic material, which consists in heating thematerial, rolling it substantially to. the desired crosssectional'shape, allowing it to cool, thenelectrically re-heating it insuccessive stages, projecting the heatcolor rays of the re-heatedmaterial onto selenium, including said selenium .in a heat regulatingcircuit and thereby regulatmg the re-heating of the material and finallysubmitting it to finishing rolling.

9.-The methodof effecting the finishing rolling of substantiallyband-shaped and similar metallic material, which consists in firstrolling the material to substantially the desired cross sectional shape,allowing it to cool, moving it-in the axial direction through a field ofsurrounding high frequency currents, thereby re-heating the material,and

finally submitting itto finishing rolling. 10. The method of effectingthe finishin rolling of substantially band-shaped an similar metallicmaterial, which consists in first rolling the material to substantiallythe desired cross sectional shape, moving it in the axial direction andfinally subjecting the material to finishing rolling and electrically're-heating it' shortly before reaching the finishin stage.

11. T e method of effecting the finishin rolling of substantiallyband-shaped an similar metallic material, which consists in firstrolling the material to substantially the desired cross sectional shape,moving it in the axial direction, allowing it to cool, and passing it incontact with spacedly disposed electric electrodes, including some ofsuch electrodes in an electric circuit, tapping said circuit at certainadjustable points, connecting said points with the other electrodes inmultiple connection, passing an electric current through said circuitsand said multiple connection and finally submitting the thus re-heatedmaterial to finishing rolling.

12. The method of efiecting the finishin rolling of substantially bandshaped an similar metallic material, which consists in desired crosssectional shape,-moving it in the axial direction and while in motionpass ing it in-contact with spacedly disposedi pairs of rollerelectrodes, each of said rollers being adapted to move in paths inclinedto the travel of the band whereby upon the rollers being displaced bythe movement of the traversing band a pressing of the rollers againstthe band is effected, passing an electric current through the electrodesand through the material and finally submitting the material tofinishing rolling.

13. In a device of the character described in combination, preliminaryrolling means and finishing rolling means spaced therefrom, a luralityof electric electrodes spacedly disposed intermediate the rolling means,an electric circuit on such electrodes, a controlling circuit connectedto the other spacedly disposed electrical electrodes formaking contactwith the material to be rolled comprising means cooperating with theelectrodes and intermediate said rolling means and an electriccircuitconnected to said electrodes. v

15. In a device of the character described in combination preliminaryrolling means and finishing rolling means spaced from said preliminaryrolling means, a plurality of pairs of superimposed roller electrodesspacedly disposed between the rolling means for making contact with thematerial to be rolled, inclined socket bearin s for supporting saidroller electrodes, adjusting means on said inclined socket bearings, andan electric circuit connected to the electrodes.

16. In a device of the character described in combination preliminaryrolling means and finishing rolling means spacedly dis posed from eachother, a plurality of electrodes. spacedly disposed intermediate therolling means, an electric circuit connected to said electrode, acontacting cir-. cuit cooperating therewith, a selenium cell in thecontrolling circuit adapted for 1 irradiation and responsive to thecolor of the in combination preliminary rolling means and finishingrolling means spacedly disposed from .each other for rolling band shapedand. similar material, conveying rollers spacedly disposed from the'rolling means, electric heating means disposed be- 3 tween theconveying rollers and the rolling means, and heating coils surroundingsaid heating means.

18. The method of effecting the finishing rolling of substantiallyband-shaped and 2 similar metallic material, which consists in firstrolling the material to substantially the desired cross sectional shape,moving it-in the axial direction and while inmotion passing it intocontact with spacedly disposed I pairs of roller electrodes, each ofsaid roller electrodes being adapted to move in paths inclined to thetravel of the band and limited in travel by adjustable stops, wherebyupon the rollers being displaced by the movement of the traversing banda pressing of the rollers against the band effected, passing an electriccurrent through the electrodes and through the material and finallysubmitting the material to finishing rolling.

19. In a device of the character described in combination preliminaryrolling means and finshing rolling means spaced from said preliminaryrolling means, a plurality of 10 spacedly disposed electrical electroderollers for making contact with the material to be rolled, said rollershaving an outer periphery adapted to make a plurality of contacts,comprising means cooperating With the electrodes and intermediate saidrolling means, and an electric circuit connected to said electrode. a

In testimony whereof I afiix my signature.

BRUNO WITTING.

